1. Field of the Invention
The present invention is directed to a refrigerant compressor, and more particularly, to a slant-plate type compressor, such as a wobble-plate type compressor, suitable for use in an automotive air-conditioning system.
2. Description of the Prior Art
Wobble-plate type compressors for use in an automotive air-conditioning system are well known in the art as disclosed in U.S. Pat. No. 4,586,874, hereby incorporated by reference, corresponding to Japanese patent application publication No. 60-135680, and shown in FIG. 1. Wobble-plate type compresser 10 includes closed cylindrical housing assembly 11 including cylinder block 111 having an open end, front end plate 13 disposed on the open end of cylinder block 111, and rear end plate 14 disposed on an opposite end of cylinder block 111. Cylinder block 11 includes a plurality of peripherally disposed cylinders 101 formed therethrough at a rearward portion, and a peripheral wall extending forward of the rearward portion to the open end. Front end plate 13 encloses crank chamber 12 within cylinder block 111, forward of the location of cylinders 101. Central bore 112 is formed through a central location of the rearward portion.
Drive shaft 15 extends through an opening in front end plate 13, and into central bore 112 formed in cylinder block 111. Drive shaft 15 is rotatably supported within central bore 112 by a bearing, such as radial needle bearing 16. Threaded portion 112a of central bore 112 is located to the rear of the inner axial end surface of drive shaft 15. Adjusting screw 17 is screwed into threaded portion 112a of central bore 112 such that rotation of screw 17 canges its axial position in bore 112. Thus, the axial position of drive shaft 15 can be adjusted as well by rotating adjusting screw 17.
Spring member 18 is disposed between the axial end surface of drive shaft 15 and adjusting screw 17. Additionally, thrust needle bearing 19 is disposed between the axial end surface of drive shaft 15 and spring member 18, assuring smooth rotation of drive shaft 15 within central bore 112. Bearing 19 also prevents the transfer of rotational motion from drive shaft 15 to adjusting screw 17 via spring member 18. Therefore, adjusting screw 17 maintains its axial position during operation of the compressor and, the axial position of drive shaft 15 will not be unintentionally adjusted during compressor operation. However, thrust needle bearing 19 is expensive, and the use of a thrust needle bearing in the compressor not only increases the cost of the compressor, but also complicates the process of assembling the compressor.